Ive had a Pioneer head unit put in m car. It was done by a pro but they said it was easy but had to buy the correct wiring harness for the steering wheel controls. They got a black frame that fits perfectly around the unit so it looks stock.
Reverse camera and everything works well

This is very good. I want to do the same as you did. Do you still have any information on the exact components you used i.e. the speakers and the amplifier? I have tried to find the one you used on the internet to no avail.

You are right about the quality of the sound. I can not use AM as the sound quality is really poor. I bought the pajero glx at a cheap price so expected to have to change a few things.

With a bit quarantine time on my hands i finally got around to installing some new front speakers. The difference in sound is unbelievable.

For my next project i was looking to do the 2nd row door speakers, i've read rumours somewhere that it is possible to get 6x9 speakers in the existing speaker holes, is anyone able to confirm?

Definitely possible on a short wheel base the stock rear speaker is from memory a 6.5" but is mounted into a oval plastic mount that is fastened to the body of the pajero. I'm not sure though if the long wheel base uses the same setup in the rear doors.

Note: with putting 6*9s in the the SWB I did have to make up my own spacer and mount that to the body.